Process for avoiding and rendering harmless the precipitates of water insoluble metal salts



252. UUMlUbl l mo.

Patented May 6, 1941 PROCESS FOR AVOIDING AND RENDERING HARMLESS THE PRECIPITATES OF WATER INSOLUBLE MIETAL SALTS Ferdinand Miinz, Frankfort-on-the-Main, Germany, assignor, by mesne assignments, to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application October 22, 1936, Serial No. 107,020. In Germany October 30, 1935 7 Claims.

My present invention relates to a process for avoiding and rendering harmless precipitates of water insoluble metal salts more particularly the precipitates formed owing to the hardness of water.

A large number of various protective colloids are already known which are capable of avoiding in soaping processes the precipitation of calcium salts of hard water in a coarse form or of dispersing the precipitates formed. They are useful for avoiding chalky stains on textile goods but they are unable to avoid loss of soap in hard water since the dispersed chalky soap does not foam and has no detergent power, nor can they prevent the precipitation of calcium carbonate occurring particularly at higher temperatures and in the presence of alkalies, which precipitates may likewise be deposited on the textile goods. In many cases other is which tend to form scarcely glllhlcmninsoluble precipitates may have a distyLbinaaefiect. Thus water containing iron effects, as itis well known, a strong turning of the goods to yellow and injures the shade of some dyestuffs. When textile goods are washed in zinc lined vessels even precipitates of zinc soaps may be formed on the goods.

Generally aluminium soaps are used for waterproofing goods. If it is required to render such goods wettable again it is often necessary to remove the aluminium salts from the fiber.

According to my present invention there are added to aqueous liquors containing metal salts of the aforesaid type organic aminocarboxylic acids containing in relation to one basic nitrogen atom more than one carboxylic acid group stand- ;ing in a-position thereto. When adding these lsubstances to aqueous liquors in the presence of metal salts which tend to form or have already formed difficultly soluble or insoluble precipitates particularly to hard water such precipittates are made harmless under particularly fa- .vorable conditions.

In all the above cases the addition of the said aminocarboxylic acids which mostly have no colloid character is of great advantage. Hard water which contains such an addition acts as soft water towards agents which precipitate chalk. It may be that the said aminocarboxylic acids bind the calcium-ion in a complex form. In consequence thereof one needs no more soap for washing when using hard water containing such an addition than in the case of distilled water.

The same good result is obtained when adding the aforesaid substances to aqueous liquors apv i t plied for other improving processes for textile goods, such as for dying processes.

Even when using dyestuffs which are not sensitive towards chalk, precipitates of calcium carbonate may occur. Dyestuffs which are sensitive toward chalk form precipitates of insoluble salts. In all these cases the addition of the aforesaid products is of advantage.

Likewise existing precipitates of insoluble calcium or other metal salts can be redissolved without using strong acids which may be detrimental to fabrics and apparatus.

In many cases of particularly insoluble salts, for instance of barium sulfate and calcium oxalate, by adding the aforesaid amino carboxylic acids an entirely clear solution is not obtainable, but the formation of the precipitates only occurs slowly and in a finely dispersed state.

There exists a great number of aminocarboxylic acids of the aforesaid type which are useful for the present process of which only some examples can be named. Among the simplest compounds which are obtainable by acting with ammonia on monochloracetic acid or by saponifying nitrils the trirnethylamine-m,a'.a"- tricarboxylic acid or nitrilotriacetic acid of the formula:

CHLCOOH I NCHa.COOH .902-;

(Beilstein, fourth edition, volume IV, page 369) is particularly suitable. The iminodiacetic acid of the formula:

CH2.COOH

CHi-COOH CHaC O OH Alkyl-N CHI-C O OH Examiner 252. COMFOSiiiONS.

are essentially more effective than the less useful aryliminodiacetic acids of the formula:

CH:.COOH

ArylN CH2.COOH

But if the latter contain in the benzene nucleus an acid group standing in ortho position to the carbon atom to which the iminogroup is attached the efficacy is essentially increased, for instance the anthranilic-NN-diacetic acid of the formula:

CIlaCOOH cmcoon coon (Beilstein, fourth edition, vol. 14, page 354) is alkyior arylgroups suitable compounds are obtained, for instance C-phenyl-nitrilotriacetic acid of the formula:

cm. 0 on C-monomethyl-nitrilotriacetic acid,

" C-dimethyl-nitrilotriacetic acid of the formula:

/CH2.COOH N-CH2COOH C.COOH CH1 CH1 C-cyclohexenyl-nitrilotriacetic acid of the formula:

cincoon These aminocarboxylic acids, which correspond to the aforesaid general formula, have more or less the said effect in an aqueous medium according to their chemical constitution.

As pointed out above one may make use of this effect generally for washing, deterging and other improving processes of textile goods, but likewise for washing or treating otherwise subjects of various use, such as pieces of furniture, floors, windows, animal hairs and the like.

Such washing and deterging and the like liquors may contain besides the aforesaid aminocarboxyiic acids further ingredients, which due to the presence of the aminocarboxylic acid can exhibit their own effect for instance in hard water in the same manner as when applied in soft water free from metal salts. Such an ingredient is particularly soap, but also other deterging agents, 1. e. besides the salts of the'higher fatty acids (the soaps) salts of sulfonic acid deriva- Aminocarboxylic acids which.

. grs.

tives of aliphatic and aromatic hydrocarbons, for instance alkylated naphthalene sulfonic acids, water soluble salts of acid sulfuric acid esters of higher aliphatic alcohols such as of lauryl-, cetylor oleyl-alcohol, salts of condensation products of fatty acids with for instance hydroxyor aminoalkylsulfonic acids and the like.

Such bodies may be previously mixed with the present aminocarboxylic acid and the mixture may be added to the liquors in question or the single ingredients may be added in any sequence in suitable properties of weight to the aqueous liquors.

To such mixtures further ingredients may be added such as sodium sulfate, sodium carbonate, silicates and phosphates, oxidants or reducing agents such as perborates and hydrosulflte, organic servants an e like.

In order to further illustrate my invention the following examples are given, the parts being by weight and all temperatures in centrigrade degrees and the degrees of hardness of the water being German degrees. But I wish it, however, to be understood that my invention is not limited to the examples given, nor to the exact conditions stated therein.

Example 1 To hard water containing 0.2 gram of calcium oxide per liter 2 grs. of the sodium salt of trimethylarnino-a-a-u-tricarboxylic acid per liter are added care being taken to establish an alkaline reaction by adding a small quantity of sodium carbonate. On adding thereto while hot 1 to 2 grs. of soap per liter a clear strongly foaming solution of very good detergent power is obtained. Such an aqueous liquor exhibits no precipitate of calcium carbonate even when boiled with the addition of sodium carbonate or caustic soda.

Instead of the tricarboxylic acid one may use the iminodiacetic acid but with a somewhat reduced effect.

Example 2 A cotton tissue, which has been repeatedly washed with hard water and is therefore strongly intermingled with precipitates of chalky soap, containing according to analysis 1.5% of calcium oxide and after treatment with hydrochloric acid 10.5% of fat which can be extracted, is treated for about an hour with a boiling liquor which has been made alkaline and contains in the liter of the trimethylamine-a-a-a"-tricarboxylic acid. After washing out and drying the chalky soap has been practically removed from the goods. The tissue contains according to analysis 0.05% of calcium oxide and 0.6% of fat.

Example 3 To a hard water containing 0.1 gram of calcium oxide per liter 1% of its weight of crystallized sodium metasilicate-pentahydrate and 0.05% of its weight of the sodium salt of the trimethylamine-tricarboxylic acid are added. When boiling oil the liquor a clear solution is obtained. whereas without such an addition fiocky precipitates are formed.

Example 4 To 100 parts of a solution containing parts of an aminocarboxylic acid obtainable by entirely hydrolizing albumen parts of monochloroacetic acid and parts of sodium carbonate are added. By heating the mixture for Examiner 10 to 12 hours at 95 to 100 C. and drying it a brownish powder is obtained which is likewise able of making harmless the hardness of water and of avoiding precipitates of calcium salts.

Example Cotton yarn is dyed with 3% of its weight of Sirius light green BL (Schultz, Farbstofitabellen, (1934) first volume of addition, page 131) with the addition per liter of grs. of sodium sulfate and 5 grs. of the sodium salt of the methyliminodiacetic acid (Beilstein, fourth edition, vol. IV, page 367) for about an hour at 90 to 95 C. while using a hard water containing 0.12 gram of calcium oxide per liter.

The goods are dyed in an unobjectionable manner whereas without the addition of the methyliminodiacetic acid the goods are dyed unequally owing to the sensitiveness of the dyestuff towards chalk.

Example 6 Cotton goods in the form of cops or cross bobbins are dyed on any usual dyeing apparatus with of its weight of a paste of Indanthrene scarlet B (Schultz, Farbstofitabellen, vol. II (1932), page 132) according to a process usual for such a vat dyestuif while using a hard water containing 0.15 gram of calcium oxide per liter, to the dyeing liquor per liter 3 grs. of the sodium salt of the anthranilic-N,N-diacetic acid being added. The goods are dyed in an unobjectionable manner whereas without such an addition white dusty precipitates of calcium salt are formed.

Example 7 When using in Example 1 instead of the sodium salt of the nitrilotriacetic acid mentioned therein the same quantity of the sodium salt of the C-phenyl-nitrilotriacetic acid likewise a clear well foaming solution is obtained.

The aforesaid acid may be prepared as follows: A mixture of 150 parts of a-aminophenylacetic acid (Beilstein, fourth edition, vol. 14, page 460), 285 parts of monochloroacetic acid, 375 parts of sodium carbonate and 800 parts of water is slowly heated to 95 to 100 C. and after stirring for some hours at this temperature 470 parts of hydrochloric acid of B. are added. After some time the C-pheny1-nitrilo-triacetic acid separates as a white crystalline powder.

The C-dimethyland C-cyclohexenylnitrilotriacetic acid which are obtainable in an analogous manner have a similar efiect.

Example 8 According to one of the usual methods 2 grs. of 2.3-hydroxynaphthoic acid-B-naphthalide are dissolved in a caustic soda solution with the addition of hot water while using a hard water containing 0.12 gram of calcium oxide per liter and further on adding per liter 3 grs. of the sodium salt of the iminobissuccinic acid of the formula:

C13H2.COOH (H.COOH

CELCOOH CH2.COOH

(which salt is obtainable by saponifying by means of an alcoholic caustic soda solution the ethylic ester cf. Beilstein, vol. IV, page 486). The solution remains clear and goods dyed in the usual manner are fast to rubbing. Without the addition of the aforesaid salt precipitates are formed and in consequence thereof goods similarly dyed are not fast to rubbing.

Example 9 In the same manner as described in the foregoing examples the ethylene-bis-(iminodiacetic) acid of the formula:

EOOC.H2C CH2.COOH

N.C:H4.N

HOOC.H2C CHQ-COOH may be used. It may be prepared either by saponifying the corresponding nitril or by acting with monochloro-acetic acid on ethylene diamine for instance in the following manner: 60 parts of ethylene diamine in an aqueous solution of 10% strength are mixed with 466 parts of the sodium salt of monochloroacetic acid and 212 parts of sodium carbonate and the mixture is heated at to C. for 8 to 10 hours. Then 470 parts of a hydrochloric acid of 20 B. are added. When cool, the aforesaid acid precipitates. It is dimculty soluble in cold water and may be recrystallized from water.

Example 10 Cotton goods are dyed as described in Example 6, but while adding per liter 2 grs. of the sodium salt of an acid of the formula:

which is obtainable in an analogous manner as the acids used in Examples 7 and 9 by acting with an excess of monochloroacetic acid on parahydroxyphenylalanine (Tyrosin).

Example 11 10 parts of the sulfuric acid ester of oleylalcohol (or of another synthetical deterging agent) are mixed with 15 parts of sodium perborate, 20 parts of sodium silicate, 15 parts of the sodium salt of the nitrolotriacetic acid and 40 parts of sodium chloride. In this manner a deterging agent very suitable for boiling washing processes which is clearly soluble even in hard water is obtained.

Gila-COOK Example 12 Example 13 To a solution containing per liter 10 grs. of barium chloride and 30 grs. of the sodium salt of the trimethylamine-tricarboxylic acid a con- 252. COMPOSlTlONS.

centrated solution of 10 grs. of sodium sulfate is added. At first the solution remains clear and becomes strongly turbid only after standing for some time. The barium sulfate which precipitates in a very fine state begins to sink down only after some hours.

Such a solution may be advantageously used for tarnishing artificial silk.

As it appears from the foregoing examples the most valuable compounds are aminocarboxylic acids of the general formula:

GHQ-CODE x-cin-000n wherein R stands for one of the radicles CHr-COOH -ci1iiN cm coon and C COOH c ll i X representing a member of the group consisting of CH2, H-C-alkyl, C=diall;yl, H-Cphenyl and C=cycloalkyl.

I claim:

1. Process for avoiding and rendering harmless precipitates formed from hard water salts, which comprises adding to hard water an alkali metal salt of the aminocarboxylic acid of the formula:

CH:.COOll 2. Process for avoiding and rendering harmless precipitates formed from hard water salts, which comprises adding to hard water an alkali metal salt of the aminocarboxylic acid of the formula:

3. The process of avoiding and rendering harmless precipitates of water insoluble metal salts which comprises adding to water containing salts of diand trivalent metals alkali metal salts of carboxylic acids of the general formula:

caicoon x-cnlcoon wherein R stands for a member selected from the group consisting of the radicles R1 standing for a member of the group consisting of hydrogen, alkyl and phenyl and R1 standing for a member of the group consisting of hydrogen and alkyl.

Cross Reference 4. The process of washing which comprises adding to hard water alkali metal salts of carboxylic acids of the general formula:

/CH:COOH x-omcoon wherein R stands for a member selected from the group consisting of the radicles R1 standing for a member of the group consisting of hydrogen, alkyl and phenyl and R2 standing for a member of the group consisting of hydrogen and alkyl, adding a Water-soluble detergent of the group consisting of salts of sulfonic acid derivatives of aliphatic and aromatic hydrocarbons, salts of acid sulfuric acid esters of higher aliphatic alcohols, salts of -condensation products of fatty acids with hydroxy alkyl sulfonic acids and salts of condensation products of fatty acids with amino alkyl sulfonic acids to the water and washing the materials to be cleansed with the water thus treated.

5. The process of washing which comprises adding to hard water alkali metal salts of carboxylic acids of the general formula:

/CH2COOII 5 N CBiCOOH wherein R stands for a member selected from the group consisting of the radicles R1 standing for a member of the group consisting of hydrogen, alkyl and phenyl and R2 standing for a member of the group consisting of hydrogen and alkyl, adding a water-soluble soap to the water and washing the materials to be cleansed with the water thus treated.

6. As a washing composition a mixture consisting of a water-soluble soap and an alkali metal salt of a carboxylic acid of the general formula:

cmcoon x-crncoon Examiner wherein R stands for a member selected the group consisting of the radicles from R1 standing for a member of the group consisting of hydrogen, alkyl and phenyl and R: standing for a member of the group consisting of hydrogen and alkyl.

'7. As a washing composition a mixture consisting of a water-soluble detergent oi the group consisting of salts of suifonic acid derivatives of aliphatic and aromatic hydrocarbons, salts of acid sulfuric acid esters of higher aliphatic alcohols, salts of condensation products of fatty acids with. hydroxy allzyl sulfonic acids and salts of condensation products of fatty acids with amino alliyl SLfl-fOIliC acids and an alkali metal salt of a carboxylic acid of the general formula:

CHcC O OH x-cmc oon wherein R stands for a member selected from the group consisting of the radicles cilia ooii R1 ancling for a member of the group consisting of hydrogen, a kyl ncl phony; and R: standing for a member of the group consisting of hydrogen and allz'gl.

FERDINAND MUNZ. 

